CrystalNES

A NES Emulator written in Crystal

Current status

• [x] Complete CPU
• [x] Controller
• [ ] PPU
  • [x] Basic background rendering
  • [x] Sprite rendering
  • [ ] Correct timings
• [ ] APU
• [ ] Mappers
  • [x] Mapper 0 / NROM
  • [ ] Mapper 1 / SxROM
  • [ ] Mapper 2 / UxROM
  • [ ] Mapper 3 / CNROM
• [ ] GUI
  • [x] PPU output
  • [x] CPU Flags and Register values
  • [ ] Disassembler
  • [ ] Debugger

Usage

raylib needs to be installed on the system.

crystal run main.cr -- path/to/rom.nes

Key mappings

Key	NES Function
A	Select
S	Start
Y/Z	A
X	B
Up	Up
Right	Right
Left	Left
Down	Down
R	Reset
Space	Play/Pause

References

Nesdev Wiki

6502 Reference